1. Technical Field
The invention relates generally to optical modules, and particularly to a lens module and an optical module incorporating the lens module.
2. Description of Related Art
Currently, along with the development of electronic devices with multiple functions, image pick-up apparatuses have become widely used in a variety of consumer electronic devices, such as notebook computers, personal digital assistants (PDAs), cellular telephones, etc. In the meantime, there is an increasingly demand for improving image quality, which is essentially depended on the quality of a lens module of the image pick-up apparatus. That is, a lens module with high image quality is desired.
A lens module generally includes a barrel, a plurality of lenses received in the barrel. In addition, the plurality of lenses is assembled along an axis direction of the barrel in order to perform optical function.
In such case, in order to ensure that the lenses can be precisely and firmly mounted inside the barrel, the lenses must be precisely manufactured with the external diameter thereof substantially equal to the inner diameter of the barrel. However, the equal diameters may cause friction between the lateral sides of the lenses and the inside wall of the barrel. Therefore, it is understood that the friction makes it difficult to assemble the lenses with the barrel. Accordingly, the lenses may be placed improperly in the barrel, e.g. not straightly. As a result, the assembling efficiency is lowered and the image quality of the yielded lens module is unsatisfactory. Furthermore, yield for lens module is reduced and cost for that is raised.
What is needed, therefore, is a lens module having improved efficiency on assembling and improved performance on optical quality.